The present invention relates to mobile robots. Mobile robots are typically designed to be either remotely controlled or are autonomous. One of the big challenges in regard to mobile robots is manoeuvring them up and down stairs, over obstacles and uneven terrains.
It is known to those skilled in the art that by extending the wheel base or track base the ability of the mobile robot to manoeuvre stairs and overcome obstacles can be enhanced. There have been some devices that have been suggested which attempt to extend the wheel or track base. Specifically, United States published patent application U.S.20080277172A1, published Nov. 13, 2008 to Ben-Tzi et al. shows a mobile robot wherein the first link has the function of acting as a first link of an arm as well as a chassis with tracks on each side, and the second link may be deployed from one end thereof so as to extend the track base. The second link is pivotally attached to first link. Alternatively United States published patent application U.S.20080296853A1 published Dec. 4, 2008 to Langord et al. shows a platform-mounted manipulator arm with a ski attached to a first link to assist in stair climbing. The first link is pivotally attached to the chassis. As well, the PackBot™ mobile robot has a pair of tracked flippers pivotally attached to either side of the chassis at one end thereof. The PackBot™ is shown in U.S. Pat. No. 6,263,989 issued Jul. 24, 2001 to Won and related patents. Another alternative was shown in U.S. Pat. No. 7,493,976 issued Feb. 24, 2009 and U.S. Pat. No. 7,600,592 issued Oct. 13, 2009 to Goldenberg et al. those show a right and left planetary wheel which may be used to extend the track base.
With regard to all of these prior art mobile robots their versatility is limited because the first link is pivotally attached to the platform or chassis with only one degree of freedom. Accordingly the range of motion is limited and the flexibility in the utility of the first link is limited. Further, particularly in regard to U.S. Pat. No. 6,263,989 and U.S. Pat. No. 7,600,592 the tracked flipper and the planetary wheel are single purpose devices. As well, both the US patent applications U.S.20080277172A1 and U.S.20080296853A1 use sliding friction between the first arm/link and stairs to improve mobility. However, this sliding friction will cause a reduced working efficiency and possible failure due to the arm/link wear-out. U.S.20080296853A1 attaches a ski structure on the underside of the first link of the arm in an attempt to reduce the friction.
Accordingly the present invention would be advantageous to provide a mobile robot with a dual purpose manipulation arm that is attached to the chassis of the robot by way of a turret. Thereby the manipulation arm may be deployed to the sides of the robot as well to the front and the back. As well, the manipulator arm is adapted to be used to increase the wheel or track base, as well as for other functions. The mobile robot of the present invention has the ability to lift its front pulleys or wheels forward and upward thus increasing it ability to ascend and descend stairs and to manoeuvring around obstacles. As well, the mobile robot of the present invention can adjust the position of its centre of gravity to protect it turning over while ascending and descending stairs and manoeuvring around obstacles.